A header include file (_header.inc) can be uploaded to the root of your site, in order to add code between the <head> tags of all your pages. This can be useful when needing to include such things as snippets of marketing code designed to monitor and tally page visits, etc.
By default, when a file named _header.inc is added to the root of your site and published, its content will be inserted between the <head> tags of all your site's pages.
To setup the _header.inc for your site, you will need to first create a plain text file on your computer, for example new_file.txt. Note, depending on your operating system's settings, the .txt extension may be hidden when displaying the filename of this file.
Login to OU Campus and navigate to the root folder for your site. Then, click the Upload button above the folder content list.
Using the Upload to dialog box, select the plain text file you created earlier, either by dragging it to the appropriate place or by using the green Add button. Hover over the added file and select Rename from the Status / Options column, and rename it to _header.inc.
When done, click the blue Start Upload button.
Depedning on how you prefer to work, you can either upload a new copy of your _header.inc file, overwritting the existing, every time you would like to make a change, or you can edit the file directly from the WYSIWYG's Edit HTML Source dialog.